The cult has found a place, far enough outside of a town that they won't be disturbed as they conduct their experiments: using a fire-god, and various other elementals to create a powerful spirit force.
For the boy they put it into - already with fire powers - it's hard, to do what they want him to do. The fire had always been close to the surface, even before-
-Even before they'd put this...whatever. Into him, that keeps escaping, and overpowering his attempts to keep the fire under control and-
And they don't like it. They get angry at him and have to punish him and-
He tries though.
But as far outside of a town as they are, the cult isn't going to manage to escape notice forever.